Ch. 6 Part Two: Marston Industries uses the periodic inventory system. The data presented below is from the accounting records of Marston for the year ended December 31, 2016: Sales Sales discounts Purchases Purchase returns Beginning inventory Ending inventory Operating expenses Transportation-in Beginning retained earnings Purchase discounts $585,000 3,000 420,000 5,000 33,000 37,000 146,000 10,000 71,000 2,000 Required: 1. Calculate Marston's net purchases for 2016. 2. Calculate Marston's cost of goods available for sale for 2016. 3. Calculate Marston's cost of goods sold for 2016